A glass run channel may be mounted along a window-receiving cavity formed in a vehicle door. The glass run channel may include features which resiliently contact the window glass to form one or more seals which help prevent wind, noise, moisture, etc. from migrating from an exterior of the vehicle into the occupant compartment. However, road noise, wind and any other noise from outside the vehicle may pass through the outer panel of the door and into the door interior. This noise may then travel into the vehicle occupant compartment through any open sound paths available. In addition, mechanisms inside the vehicle door may also produce noise that may enter the occupant compartment. For example, in a vehicle sliding door, a pulley mechanism may be housed inside the door to aid in automatically opening and closing the door. This mechanism generates noise that may enter the occupant compartment through openings in the door structure.